1. Field of the Invention
The present invention relates to a package equipped with a semiconductor element operated with a low loss in radio frequencies (RF), which can be realized at a low cost.
2. Discussion of Background
In case that operating frequencies of semiconductor devices are increased, structures of joining a semiconductor element to a ground surface of a package and/or grounding the package itself are significant. Conventionally, so-called via hole is opened at a ground in a semiconductor element in a downward direction to connect a package with the ground, or a metallic package, specifically for a ground surface, is used to stabilize the ground surface.
However, in recent years, there is a tendency of pursuing low costs of these devices operating at high rates. Therefore, it becomes difficult to apply via holes and/or metallic packages to such semiconductor elements. Instead thereof, connections to grounds are being attained by bonding wires, or packages having ceramic bases are being used for secure groundings. When operating frequencies become 1 GHz or more, grounds themselves may have components of inductance (L) depending on bonding wires and/or arrangements of packages and ground surfaces, whereby properties of semiconductor are caused to be deteriorated.
FIG. 6 shows a conventional package structure. In FIG. 6, numerical reference 1 designates a ceramic package; numerical reference 2 designates a semiconductor element; numerical reference 3 designates an inner lead wire for electrically connecting an outer circuit to the semiconductor element; numerical reference 4 designates an Au wire; numerical reference 5 designates a ground area having a structure of metallizing a ceramic; numerical reference 6 designates a jointing material for connecting the semiconductor element 2 to the package 1; and numerical reference 7 designates an antirunning, being a pattern clipping the metallized ground area portion, for preventing the jointing material from flowing at a time of bonding the Au wires 4 between ground terminals of the semiconductor element 2 and the ground area 5 of package, wherein the wires are bonded on outer sides of the antirunning portions.
FIG. 7 is a cross-sectional view of this package, in which numerical reference 50 designates a grounding area positioned just below the semiconductor element 2 on plating of the package.
However, the conventional semiconductor package for radio frequency has problems that properties of the semiconductor element 2, specifically including a gain, were deteriorated because there were distances between a semiconductor element 2 and a metallized ground area 5 and between wire bonding and a ground surface just below the semiconductor element 2 and such distances of arrows 100 shown in FIG. 8 caused inductances of L components.